1. Field of the Invention
The present invention relates generally to the attachment of elastomeric sleeves to elongate articles, such as, for example, the attachment of tubing to joints, fittings or welds, or the attachment of grips to hand tools such as hammers, screw drivers, wrenches and the like, or to sports equipment such as golf clubs, tennis racquets, baseball bats and the like. More specifically, the invention relates to temporarily expanding such sleeves using swelling solvents so that the expanded sleeve may be fitted over an elongate article, such as a hand tool or a grip-receiving portion of a golf club shaft, and contracted by evaporating the swelling solvent therefrom to bring the sleeve into tight contact with the article.
2. Discussion of Related Art
It is known in the art that certain types of elastomeric tubing can be used for protecting joints, fittings and welds, so long as such tubing can be placed into tight and intimate contact with the surface which it surrounds. There are a wide variety of situations where it is desirable or necessary to tightly fit an elastomeric sleeve over an elongate article, such as, for example, to seal a joint, to electrically insulate or to prevent corrosion of the article if it is exposed to the elements. There have been developed in the prior art ways to attach such an elastomeric sleeve to an elongate article, including the use of dimensionally recoverable sleeves, which may be expanded, or which are made in an expanded state. The sleeves may be placed into position over a desired article and caused or allowed to contract into tight contact with the article.
Examples of methods and devices used in the prior art to expand an elastomeric sleeve are set forth in U.S. Pat. No. 5,406,871 to Lambert et al., U.S. Pat. No. 5,098,752 to Chang et al. and U.S. Pat. No. 4,391,661 to Izraeli. Introducing a tight-fitting elastomeric sleeve over an elongate article using these methods and devices, however, requires the manufacture of complex devices that are expensive and difficult to handle. For example, sleeves formed of an elastomeric sheet or tube may be held in an expanded state by a restraining means that can be removed or separated from the elastomeric member to permit it to recover to the unexpanded state. Contact adhesives, or other adhesives may be used to seal such a recovered article to a substrate.
Another well-known type of tubing or sleeve is the type that is originally manufactured to be larger than the size it will have in its end use. This type is the heat shrinkable type, which, when applied over a joint and subjected to heat, shrinks tightly into contact with the members forming the joint. Heat shrinkable sleeves such as tubular and wraparound sleeves may be used to enclose or cover elongate substrates such as pipes, cables, cable joints and/or splices. Such sleeves are useful for providing environmental and corrosion protection, and for providing additional structural integrity, to joints, fittings and welds by which pipes, cables, conduits and other elongated members are joined.
Another lesser-known type of shrinkable tube combines features of the above-described sleeves (i.e., one that must be mechanically expanded, and one that is manufactured in an expanded state and contracted by heating). This lesser-known type of sleeve, referred to as an "air shrink" sleeve, is the subject of the present invention, and is a tube that is originally formed in a contracted state and then treated with chemicals to bring it to a dilated or enlarged state. This type of tubing will remain in its dilated or enlarged state so long as it is kept out of contact with the air. However, once the tubing is brought into contact with the surrounding air, it tends to shrink back to its initial size, without any application of heat, and simply by the contact of the air against the sleeve. Examples of this type of sleeve may be found, for example, in U.S. Pat. Nos. 4,401,218, 4,07,866 and 4,865,890, all to Erlichman.
Air shrink sleeves known in the prior art, however, suffer from a number of disadvantages. For example, prior art air shrink sleeves are made using swelling solvents that have a number of shortcomings. Known solvents used to expand elatomeric sleeves are carcinogenic or otherwise toxic; environmentally unfriendly; have unacceptable flash points for safe shipping, storing or other handling; and/or feature unacceptable rates of expansion and contraction for a wide variety of applications.
In light of the above, there has been a long-felt need for air shrink sleeves that are prepared using evaporative compositions that have a variety of excellent features. For example, there is a great need for products made from compositions that are not toxic; that are not harmful to the environment, specifically the ozone; that have acceptably high flash points for purposes of safe storage and transportation; and that evaporate quickly enough to provide an expanded sleeve the ability to shrink rapidly. The present invention provides novel methods and compositions that exhibit a number of advantageous features when used for the placement of an elastomeric sleeve on an elongate article. Sleeves made in accordance with the invention may be readily attached to an article without the need for specific skill or training, thereby eliminating the inconvenience and delay caused by the time-consuming and labor intensive manner of placing such a sleeve using prior art techniques and products.